How baleen whales talk to each other through complex vocalizations

A team of scientists has uncovered the mechanism behind the complex vocalizations of baleen whales, the largest animals on Earth. This revelation comes after more than half a century of mystery surrounding how these marine giants produce their distinctive songs, essential for communication across the vast, murky oceans they inhabit.

Limited communication range of baleen whales

Led by voice science experts Professor Coen Elemans from the University of Southern Denmark and Professor Tecumseh Fitch from the University of Vienna, Austria, the study found that baleen whales have evolved unique structures in their larynx for producing low-frequency vocalizations.

This adaptation, however, also imposes limitations on their communication range.

“The toothed and baleen whales evolved from land mammals that had a larynx serving two functions: protecting the airways and sound production. However, their transition to aquatic life placed new and strict demands on the larynx to prevent choking underwater,” Fitch explained, highlighting the evolutionary pressures that shaped these adaptations.

The researchers discovered significant modifications in the whales’ larynx, particularly the arytenoids – tiny cartilages in the larynx responsible for adjusting vocal folds – which have transformed dramatically in baleen whales. 

“The arytenoids changed into large, long cylinders fused at the base to form a large U-shaped rigid structure that extends nearly the full length of the larynx,” said Elemans. 

“We found that this U-shaped structure pushes against a big fatty cushion on the inside of the larynx. When the whales push air from their lungs past this cushion, it starts to vibrate and this generates very low frequency underwater sounds.”

Increasing levels of human noise

This study not only sheds light on the acoustic capabilities of these majestic creatures but also underscores the challenges they face due to increasing levels of human-made noise in the oceans. 

“Regrettably, the frequency range and maximum communication depth of 100 meters we predict, overlaps completely with the dominant frequency range and depth of human-made noise caused by shipping traffic,” Elemans pointed out, indicating the potential threat to whale communication.

“The first acoustic recordings of humpback whale song by Roger and Katy Payne in 1970 resonated with humanity profoundly, started the flourishing field of marine bioacoustics, and sparked global interest in marine conservation efforts,” Elemans added. “Now we show that despite their amazing physiology they literally cannot escape the noise humans make in the oceans.”

This study – published in the journal Nature – not only answers long-standing questions about baleen whale vocalizations but also calls attention to the urgent need for conservation efforts to mitigate the impact of human activity on marine life.

More about baleen whales

Baleen whales are a distinct group of marine mammals known for their unique feeding mechanism, which involves baleen plates instead of teeth. These plates are made of keratin, the same material as human hair and nails, and are used to filter small fish, krill, and plankton from the water. 

Baleen whale size and distribution

Baleen whales range in size from the relatively small minke whale, which can be about 23 feet long, to the blue whale, the largest animal on Earth, reaching lengths up to 100 feet or more.

These whales are found in oceans all over the world, from the Arctic and Antarctic to tropical seas. They are known for their long migrations, traveling thousands of miles between feeding grounds in colder waters and breeding grounds in warmer waters. 

Baleen whales are also notable for their complex vocalizations, which in the case of species like the humpback whale, are considered to be a form of song and are used in communication and possibly mating rituals.

Conservation and ecological role 

Despite their massive size and being top predators in their environment, baleen whales face several threats from human activities, including ship strikes, entanglement in fishing gear, and climate change which affects their food sources. 

They are protected internationally by various conservation efforts and agreements aiming to mitigate these threats and ensure their survival for future generations. 

Baleen whales play a crucial role in marine ecosystems, contributing to the health of ocean environments through their feeding activity, which helps regulate the populations of their prey and recycle nutrients through the water column.

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